Secure meter

ABSTRACT

A compact multiparameter instrument for electrochemical measurements is described. The instrument facilitates rapid engagement and disengagement of a variety of sensor elements in such a manner as to prevent accidental mismatch of sensor elements and sensor input ports. Positive identification of specific sensors is ensured by including color marking or other indicia on the sensor connectors that are matched to corresponding markings on the meter body. Measurements of specific parameters such as temperature may readily be shared among all other sensors connected to the instrument. A method of rapidly reconfiguring the instrument to provide extended or different capabilities is described.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to meters and, more particularly, to meters formeasuring a variety of parameters such as pH, dissolved oxygen, ionicconductivity, and the like.

2. Background Information

Electrochemical measurements are of significant importance in a widevariety of industries and applications. Thus, pH measurements are ofsignificant and often of critical importance in medicine andbiochemistry, as well as in food processing, pharmaceuticalmanufacturing, agriculture and other industries and applications.Measurements of the dissolved oxygen content of water are of importancein assessing the viability of lakes, streams, wells and other watercontainments. Measurement of the specific ion content of liquids withrespect to a variety of ions such as chlorine, copper, nitrate, cyanide,and others is frequently essential to assessing water safety andpotability.

Frequently, these measurements are made with instruments specific to aparticular type of measurement, e.g., pH. Multiparameter instrumentscapable of measuring two or more parameters are known, but are commonlybulky and not simple to use.

Further, it is often necessary to make the desired measurements in fieldconditions, outside the laboratory environment. In the field, theinstruments are exposed to a hostile environment, including exposure tocontamination of the instrument by dirt, water invasion, and the like asa result of carelessness or accident, such as dropping.

In constructing a meter that can meet significant standards of accuracy,reliability and ruggedness, if is, of course, essential that the meterbe competitive in the marketplace. Thus, efficient methods ofconstructing such a meter are of importance.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the invention to provide an improvedmeter.

Further, it is an object of the invention to provide a meter formeasuring various parameters in frequently unaccommodating environments.

Still a further object of the invention is to provide a meter to whichvarious sensors may quickly and easily be connected, yet which isreadily secured against inadvertent detachment of the sensors.

Further, it is an object of the invention to provide a meter which maybe constructed economically yet readily adapted to perform a variety ofelectrochemical measurements.

In accordance with the present invention, a multiparameter meter isprovided that enables a multiplicity of different types ofelectrochemical measurements. The meter is characterized by acomparatively small footprint and relatively light weight. It enablesrapid attachment of a multiplicity of differing types of sensors inwaterproof connections that are relatively secure against inadvertentdisconnection. Protection is provided against inadvertent mismating ofsensors and instrument jacks, and provision is made to facilitateassociation of a given connector with its corresponding jack. A flexiblemanufacturing arrangement facilitates rapid adaption of the meter tovarious sets of measurements.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other and further objects and features of theinvention will be more readily understood from the following detaileddescription of a preferred embodiment thereof, when taken in conjunctionwith the accompanying drawings, in which:

FIG. 1 is a plan view in perspective of a handheld meter in accordancewith the present invention;

FIG. 1A is a side elevational view of the meter of FIG. 1;

FIG. 2 is a rear elevational view of the meter of FIG. 1, shown withprotective flaps engaged with the various connector housings;

FIG. 2A is a rear elevational view of the meter of FIG. 1, shown withthe protective flaps bent downwardly to expose the various connectors;

FIG. 3 is a cross-sectional view along the lines 3-3 of FIG. 2 showingthe manner in which the protective flaps engage with a finger formed onthe meter body to secure the flaps in place;

FIG. 4A is a view in perspective of a connector constructed inaccordance with the present invention for connecting a first type ofsensor to the meter of FIG. 1;

FIG. 4B is a view in perspective of a connector constructed inaccordance with the present invention for connecting a second type ofsensor to the meter of FIG. 1; and

FIG. 5 is a side, sectional elevational view of the meter of FIG. 1,similar to that of FIG. 3, but with the protective flap of one of theconnector housings disengaged from the housing and the connector of FIG.4A inserted into the housing for mating with its corresponding connectorcomponent;

FIG. 6 is a view in perspective of the meter of FIG. 1 illustrating themanner in which the various connectors are readily secured to the meterbody;

DETAILED DESCRIPTION OF AN ILLUSTRATIVE EMBODIMENT

Referring now to FIG. 1, a meter 10 in accordance with the presentinvention has a body 12 on which are located a display 14 and a keypad16. The keypad has buttons 16 a-16 e which enable entry of commands forspecifying the type of measurement to be made and parameters associatedwith the measurement. The display presents to the user informationconcerning the measurements.

The meter 10 has a plurality of connector housings or ports 18 formed ona rear face thereof through which connection to external sensors aremade. As shown in more detail in FIG. 2A, the housings 18 a, 18 b, 18 c,18 d each surround and enclose a connector portion 20 a. 20 b, 20 c, 20d, respectively. For ease of reference only, the connector portions 20a-d located on the body 12 will be referred to herein as “jacks”, andthe portions which mate with them will be referred to a “plugs”, itbeing understood that either part of a two-piece connector may bemounted on the body as a jack, the other part then being referred to asa plug.

For reasons described more fully hereinafter, each connector portion ispreferably of a different connector type. For example, in the preferredembodiment described herein, connector portion 20 a is a locking BNCtype connector, and is used for measuring pH via ion-selectiveelectrodes; connector portion 20 b is an 8-pin mini DIN connector, andis used for connection to sensors that measure temperature andconductivity; connector portion 20 c is a 9-pin mini DIN connector, andis used for connection to sensors that measure dissolved oxygen, and pHvia field-effect transistors (FETs); and connector portion 20 d is anRN-232 type connector for carrying digital communications and power.

As shown in FIGS. 2 and 3, flaps 22 each have a grommet 28 a whichsnugly engages its corresponding housing 18 a to form a waterproof sealtherewith. Flaps 22 b, 22 c and 22 d each have an upper portion whichengages a rail 26 on the meter body and a grommet 28 b, 28 c, 28 d,respectively, intermediate the upper and lower portions which engagetheir corresponding housings 18 b-18 d. This may be seen more clearly inFIG. 3, which shows the meter body and an illustrative one of the flaps22 b-22 d, specifically, flap 22 c, in more detail. A lower portion 22c′ of flap 22 c is fixed to the bottom 12′ of the meter body. An upperportion 22 c″ of flap 22 c″ carries thereon a finger 24 c, which graspsa rail 26 on the meter body 12. The rail extends across at least aportion of the rear face of the body in at least the vicinity of theflaps 22 so as to be engageable by them. Advantageously, the rail iscontinuous along its extent but, of course, this is not necessary (forexample, the rail may be crenellated), as long as a rail portion isprovided for engagement with each flap. A grommet, e.g., grommet 28 c offlap 22 c in FIG. 3, is formed on each flap intermediate its ends 22 c′,22 c″.

The flaps are formed of rubber or other flexible material, and are eachindependently movable between a disengaged position such as shown inFIG. 2A to an engaged position such as shown in FIG. 2. When the finger24 c of one of the flaps, such as flap 22 c, engages the rail 26 of body12, the grommet 28 c of the flap engages and encloses its correspondinghousing 18 c and forms a watertight seal with it, thus protecting theconnector jack within the housing from water and other contaminants.Flaps 22 b and 22 d are similarly constructed and function similarly,and thus need not be separately described.

In FIG. 4A, an 8 pin mini DIN connector 50 in accordance with theinvention is shown. A connector portion or plug 51 comprises a standard8-pin mini DIN connector plug and is enclosed by overmolding it in abody 52, advantageously of a plastic material. The overmolding securesthe connection of the connector jack to its cable and waterproofs thisconnection. For ease of reference, the plug 51 and body 52 are referredto collectively hererin as a connector. Body 52 has an arm 54 mountedthereon in cantilever fashion. The forward end of the arm terminates ina downwardly extending finger 54′; the rear end 54″ of the connectorforms a tab on which the suer can push downwardly to raise the front endupwardly, as described below. A land 56 on the lower face of the tablimits movement of tab. The rear portion 52′ of the connector housing isserraed to provide strain relief for the cord. An inset surface 56 maybe formed on the upper face of the arm 54 to receive a label (not shown)providing information as to the specific form of sensor associated withthe connector, its manufacturer, important data concerning its, use orother desired information or identification. An electrical cable 58carries signals between the pins 60 of the connector plug 51 and asensor or other electrical component (not shown). An O-ring 62 iscarried on the forward face of the connector body surrounding the plug.

Connector 50 is designed for connection with a corresponding 8-pin jackon meter body 12, e.g., jack 20 b. A similar connector, but 9-pininstead of 8-pin, is then used to connect to its corresponding jack,e.g. jack 20 c on body 12. Because of the difference in their pin count,the connectors cannot be inadvertently plugged into the wrong jack. Thisis quite beneficial when the meter is used outside the laboratoryenvironment, where inattentive or inexperienced users could possiblydamage the meter or the sensors connected to it by making the wrongconnections to it.

FIG. 4B illustrates a BNC-type connector in accordance with the presentinvention. The connector is formed from a standard BNC connector portionor plug 71 that is enclosed by overmolding in a body 72, advantageouslyof a plastic material. An inset surface may be formed on the upper faceof the arm body 72 to receive a label (not shown) providing informationas to the specific form of sensor associated with the connector, etc. asdescribed above in connection with connector 50. An electrical cable 78carries signals between the plug 71 and a sensor or other electricalcomponent (not shown). An O-ring 82 is carried on the forward face ofthe connector body surrounding the plug 71. Again, the overmoldingsecures and waterproofs the connection between the cable 58 and theconnector plug. This is particularly beneficial in the case of BNC-typeconnectors, since the cable is normally secured to the connector plug bycrimping, thus opening the possibility of water infestation. An O-ringfurther seals the connector to the meter body when inserted into itscorresponding connector port, e.g., port 18 a (FIG. 2A). BecauseBNC-type connectors include positive locking means, no separate lockingarm, such as arm 54 on connector 50, is needed.

In similar fashion an RN-232 connector (not shown) having a plug isovermolded into a body for insertion into a plug, e.g., plug 18 d, onbody 12, for providing power and electrical communications.

FIG. 5 shows the manner in which the connector 50 is engaged with themeter 10. A flap 22 is bent downwardly by the user to expose a housing18 and thus a connector 20 jack within it. As the user moves the body 52toward a connector housing to thereby engage the pins 60 of theconnector plug with the corresponding connector jack within the housing,the O-ring 62 on the connector snugly engages the inside wall of thehousing 20 to thereby form a waterproof seal between the connector andthe housing. At the same time, the finger 54′ of the arm 54 on theconnector body 52 begins to move upwardly as it encounters the rail 26of the meter body, and then snaps downwardly to firmly engage the railand thus secure the connector (and its corresponding sensor) to themeter, thereby preventing, or at least hindering, inadvertent removal ofthe connector from the meter. To this end, the front surface 54′ of thearm 54 is rounded or downwardly tapered (e.g., an inclined plane) tocause the arm to ride upwardly on the rail as the arm is pressedforwardly against it.

In order to subsequently remove the connector from the jack, the usersimply presses down on the rear portion 54″ of the arm 54 (see FIG. 4A)to thereby move the finger 54′ above the rail 26 and disengage the two.The plug 51 can then be removed from the jack 18 by pulling back on theformer to disconnect the two. The flap 22 can then be re-engaged withthe rail 26, thereby sealing the jack housing in a waterproof manner. Apad 54 a limits the downward travel of the arm 54, thus limiting thestrain on it when is flexed by the user to release it from the meter.

As noted above, each of the connectors are preferably of different type,thus ensuring that no two of the connectors can be mated to the samejack, thereby preventing possible damage to the meter or to the sensors.This could also be accomplished by providing different shapes for theconnector bodies and corresponding shapes (e.g., round cross sections ofdiffering diameters for the connector bodies and the correspondingconnector ports; or differing cross-sections, such as square, round,hexagonal, etc. for the two.). If two or more of the connectors were ofidentical type and form, a sensor intended for one connector couldinadvertently be connected into the other, resulting in the potentialfor significant damage to the meter, the sensors, or both.

Also as noted earlier, identifying indicia may be provided on thevarious connectors or even on the cables associated with the connectors.The indicia may be of a type that is matched to a correspondingindicator on the housings containing the respective connector jacks towhich the external connector plugs are to be connected. For example, theconnector bodies 52 may be color coded for the respective sensors theyare to accommodate, and matching colors provided on the connectorhousings 20 or portions of the rail 26 adjacent the respective housings.Other indicia may be used in place of, or in addition to, color.

In making electrochemical measurements, the temperature of the liquid orother substance being measured is often of significant importance. Thus,in some measurements such as conductivity measurements, the temperatureis commonly measured as well as the conductivity itself. Thus, in thepresent invention, when a measurement is performed which commonlyrequires a measurement of temperature as well, the temperaturemeasurement is available simultaneously with the measurement of otherparameters via sensors connected to any other port on the instrumentwithout further effort.

The arrangement of connector ports described herein enables theconstruction of a compact, multiparameter instrument for electrochemicalmeasurements. Further, the construction described herein facilitatesrapid engagement and disengagement of a variety of sensor elements insuch a manner as to prevent accidental mismatch of sensor elements andsensor input ports. Positive identification of specific sensors isensured by including color marking or other indicia on the sensorconnectors that are matched to corresponding markings on the meter body.

Turning now to FIG. 7, an additional feature of the present invention isillustrated. In order to enable the efficient manufacture of metersproviding different combinations of measurement capabilities, we formthe basic meter system on a printed circuit board 90 which fits into themeter body 12. The board 90 caries connector blocks 92-98 which in turncarry the respective connector jacks 20 a-20 d shown in FIG. 1.Integrated circuit components such as component 100 in FIG. 7 mount onthe board 90 and electrically connect to the jacks 20 by carryingsignals to and from the jacks as well as to and from other components(not shown) on the board.

The components 100 provide various measurement and control capabilitiesto the instrument. To extend these capabilities, or to change them, oneor more additional boards 102 are provided. Board 102 carries a firstinterconnect segment 104 (shown in chain-link lines since it is mountedon the underside of the board) with connector pins 106 extendingdownwardly therefrom. The pins 106 fit into electrical receptacles 108in a connector 110 mounted on board 90. Additional components such asintegrated circuit 112 are mounted on board 102 and electricallycommunicate with the components 100 and connectors 20 a-d on board 90through the interconnect 104.

The arrangement described enables the capabilities of the basic meter tobe changed or extended as desired in order to accommodate differentmeasurements. The added board may extend the capabilities of the basicboard or may provide entirely different capabilities. Thus, the samebasic meter body can serve for handling a wide variety of measurementsand measurement capabilities. The change may be made quickly and easilyduring the manufacturing process, or subsequently.

1. A meter providing a secure connection to a plurality of sensorelements, said meter comprising a body having a plurality of electricaljacks thereon in generally contiguous relation for connecting saidsensors to said meter; a rail on said body adjacent said jacks andseparate therefrom for lockably engaging a finger on an electricalconnector when said connector is engaged with a jack to thereby hinderinadvertent detachment of said connector from said jack.
 2. A meteraccording to claim 1 in which said jacks extend generally in a linealong a face of said meter and in which said rail extends in acorresponding line spaced from said jacks.
 3. A meter according to claim2 in which said rail extends continuously adjacent said jacks.
 4. Ameter according to claim 1 in which said finger is so mounted on saidconnector as to enable lockable engagement with said rail only when saidconnector is securely engaged with said jack.
 5. A meter according toclaim 1 in which said connector comprises a body encompassing at leastone electrical conductive element for carrying signals between a sensorand said meter, said finger positioned on the exterior of said connectorbody for engagement with said rail when said connector is engaged with acorresponding jack.
 6. A meter according to claim 5 in which said fingeris formed on a cantilevered arm mounted on said body to thereby enableflexing in a direction transverse to said body whereby said finger maybe moved above said rail during engagement of a connector with a jackand then returned to a position behind said rail to secure saidengagement.
 7. A meter according to claim 6 in which said arm includes atab extending along said arm in a direction opposite the direction ofsaid finger to facilitate flexing of said arm by a user duringengagement of a connector with a jack.
 8. A meter according to claim 1which includes means on said connector for associating said connectorwith a specific jack on said meter.
 9. A meter according to claim 8 inwhich said means comprises a color coding on said connector matched to acolor coding on said jack.
 10. A meter according to claim 7 in whichsaid connector body encompasses a multi-pin DIN connector.
 11. A meteraccording to claim 1 in which said connector body encompasses a BNCconnector.
 12. A meter according to claim 1 including a plurality ofconnectors for connecting a plurality of electrochemical sensors to saidmeter.
 13. A meter according to claim 12 in which said plurality ofsensors includes at least a pair of sensors of different type so as topreclude inadvertent connection of a sensor of one type to a jackintended to accommodate a sensor of another type.
 14. A meter accordingto claim 12 in which said plurality of sensors includes at least a pairof sensors of different shape so as to preclude inadvertent connectionof a sensor of one shape to a jack intended to accommodate a sensor ofanother shape.
 15. A meter providing a secure connection to a pluralityof sensor elements, said meter comprising a body having a plurality ofelectrical jacks thereon in generally contiguous relation for connectingsaid sensors to said meter; a rail on said body adjacent said jacks andseparate therefrom for lockably engaging a finger on an electricalconnector when said connector is engaged with a jack to thereby hinderinadvertent detachment of said connector from said jack, said fingerbeing so mounted on said connector as to enable lockable engagement withsaid rail only when said connector is securely engaged with said jack.16. A meter according to claim 15 in which said finger is formed on acantilevered arm mounted on said body to thereby enable flexing in adirection transverse to said body whereby said finger may be moved abovesaid rail during engagement of a connector with a jack and then returnedto a position behind said rail to secure said engagement, said armincluding a finger extending along said arm in a direction opposite thedirection of said finger to facilitate flexing of said arm by a userduring engagement of a connector with a jack.
 17. An electricalconnector for lockable engagement with a rail on a meter body to hinderinadvertent disengagement of said connector from said meter, comprising:a body encompassing at least one electrical conductive element forcarrying signals between a sensor and said body and having a fingerpositioned on the exterior of said body for engagement with said railwhen said connector is engaged with a corresponding jack on said meterbody.
 18. An electrical connector according to claim 17 in which saidfinger is formed on a cantilevered arm mounted on said body to therebyenable flexing in a direction transverse to said body whereby saidfinger may be moved above said rail during engagement of a connectorwith a jack and then returned to a position behind said rail to securesaid engagement.
 19. An electrical connector according to claim 17 inwhich said arm includes a tab extending along said arm in a directionopposite the direction of said finger to facilitate flexing of said armby a user during disengagement of said connector from a jack.
 20. Anelectrical connector according to claim 18 in which said arm and fingeris integrally molded with said connector body.
 21. An electricalconnector according to claim 18 in which said connector body encompassesa multi-pin DIN connector.
 22. An electrical connector according toclaim 18 in which said connector body encompasses a BNC connector. 23.An electrical connector according to claim 18 including a plurality ofconnectors for connecting a plurality of electrochemical sensors to saidmeter.
 24. A method for rapidly changing the configuration of anelectrochemical meter, comprising: providing a first printed circuitboard having at least a first integrated circuit component thereon forproviding a first set of capabilities to said meter, said board havingmounted thereon at least a first connector element for receiving acorresponding connector element for carrying electrochemicalmeasurements to said integrated circuit; providing a second printedcircuit board having at least a second integrated circuit componentthereon for providing a second set of capabilities to said meter; andinterconnecting said first and second boards to enable exchange ofelectrical signals therebetween.
 25. A method or securely connecting ajack to a plug on an electrochemical measuring instrument, comprisingproviding a rail on an instrument body for disengageably receiving aflexible finger on a housing formed around said jack